kjavanb123
Well-known member
Rick
Thanks for the post. I plan to smelt the bead with silver then dissolve in nitric so I can check the solution for Pt.
I am smelting the coarse size concentrate right now so I can cupel the beads produced from them.
Cinnabar?
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Thanks for the post. I plan to smelt the bead with silver then dissolve in nitric so I can check the solution for Pt.
I am smelting the coarse size concentrate right now so I can cupel the beads produced from them.
Rick & Carrie
Prospectors Rick & Carrie of Geotech Analytical
Only the silver will go into solution if using nitric.
The gold and any PGM's will remain as a fine sediment.
Keep us posted with your results on smelting the course sediments.
kjavanb123
Well-known member
Rick
I was on the impression that if the content of Pt in the silver alloy is less than 25 percent, Pt also goes to nitric solution as silver does.
I believe only Os or Ir Rh would drop as black powder.
Indeed I would share my smelting and final calculations with the forum.
If this bead is PGMs gold alloy, then I will be the pioneer in discovering PGMs in the region.
Thanks
Kj
kjavanb123
Well-known member
Updates
Smelting the coarse size concentrate from 10kg sample was completed and I am cupeling the lead buttons.
Here is the picture of lead buttons from smelting.
Smelting the coarse size concentrate from 10kg sample was completed and I am cupeling the lead buttons.
Here is the picture of lead buttons from smelting.
Rick & Carrie
Prospectors Rick & Carrie of Geotech Analytical
Thanks for keeping us updated.
We noticed the iron nails in your lead prills.
It would be best to scorify those prills down to 1/3 their current weight to get rid of the iron contamination within the prills.
I do not think that it would cause precious metal loss to the cupel, though it is a contaminant.
It is faster to scorify down to 1/3 of start weight then cupel anyway.
I do it on all fire assays that we perform.
kurtak
Well-known member
Rick
That not quite true - Pd is also soluble in nitric though less so then silver so there is a very good chance that the nitric can/will dissolve both Ag & Pd (at least some Pd - &/or even all of the Pd)
In other words - concerning the dissolving of the Pd in nitric it depends on conditions as in temp of the nitric when dissolving the silver &/or percent of the Pd in the silver
Temp of the nitric - you can dissolve "pure" Pd with nitric - but - because Pd is "less" reactive (to nitric) then Ag you need to "drive" the reaction on Pd with heat (hot plate) where as silver will dissolve on the heat of its own reaction (no additional heat) --- here we are talking about Ag &/or Pd in a solid form not powders
If finely divided (powders) nitric will dissolve both Ag - or Pd - without additional heat - just that it will take longer to dissolve the Pd as it is less reactive to the nitric then Ag --- here we are talking about dissolving pure powders of Ag - or Pd
So - when dissolving alloys (of Ag/Pd) depending on percentage of Ag to Pd (how finely divided in the Ag the Pd is) you will "most certainly" dissolve some of the Pd - if not all of it (in nitric)
And - for what it is worth - nitric will dissolve Pt when alloyed with silver - IF (the BIG IF) the Pt is VERY finely divided in the silver --- I don't remember off the top of my head how finely divided (percentage) the Pt in silver has to be for nitric to dissolve Pt alloyed in silver - just that if the Pt is VERY finely divided in the silver nitric will dissolve both the silver & the Pt
Edit to add; - Bottom line - when Ag & Pd are alloyed you will most certainly dissolve both Ag & Pd with nitric - "some" Pd "may" go undissolved IF (the BIF IF) the percent of Pd is high enough - AND - Pt will dissolve in nitric IF (the BIG IF again) the Pt if VERY finely divided in the silver
Kurt
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Rick & Carrie
Prospectors Rick & Carrie of Geotech Analytical
I have also read that Palladium will stain Sulfuric Acid Orange.
If true, I have saw such with black sand samples that I was giving a Sulfuric Acid wash to in order to remove most base metals before further processing.
kurtak
Well-known member
I don't know how sulfuric reacts with Pd as I don't use sulfuric much in my refining other then using it to drop lead out of solutions
Most of my refining is done on e-waste - not ores
What I do know is that HCl alone will also dissolve Pd - BUT - it (the Pd) has to be VERY (ultra) finely divided
The only time I have dissolved Pd with HCl "alone" is when I was processing CATs - the Pd is so VERY finely divided in the wash coat of the CATs that the Pd would dissolve "instantly" when pouring the HCl on the CAT combs & before adding chlorine or nitric to the HCl
Kurt
Rick & Carrie
Prospectors Rick & Carrie of Geotech Analytical
Good info. Thanks.
kjavanb123
Well-known member
Hi
Finally cupeling the lead buttons from smelting coarse size concentrates was finished.
I produced 7 small silver beads from cupeling them. Here is a close shot of those beads.
The weight of those silver beads is 0.013 Oz ( 0.369g) which I dissolved in hot nitric acid.
Here is the bright yellow nitrate solution which didn't produce any color change with my stannous chloride testing solution.
I plan to cement any value from that solution using zinc powder.
Here is the gold powder and a doll yellow bead that didn't dissolve in hot nitric acid.
My plan is to smelt the powder and bead with silver then part with hot nitric acid to find the amount gold from smelting coarse size concentrate
That black bead resulted from smelting and cupeling fine size concentrate I also would like to smelt with silver then part with nitric acid to see how much gold and or PGM it produces.
More pictures soon.
Finally cupeling the lead buttons from smelting coarse size concentrates was finished.
I produced 7 small silver beads from cupeling them. Here is a close shot of those beads.
The weight of those silver beads is 0.013 Oz ( 0.369g) which I dissolved in hot nitric acid.
Here is the bright yellow nitrate solution which didn't produce any color change with my stannous chloride testing solution.
I plan to cement any value from that solution using zinc powder.
Here is the gold powder and a doll yellow bead that didn't dissolve in hot nitric acid.
My plan is to smelt the powder and bead with silver then part with hot nitric acid to find the amount gold from smelting coarse size concentrate
That black bead resulted from smelting and cupeling fine size concentrate I also would like to smelt with silver then part with nitric acid to see how much gold and or PGM it produces.
More pictures soon.
Geo
Well-known member
Stannous testing the nitric leach will not work unless you kill some of the excess nitric acid. The stannous chloride test acts as an ionic exchange and precipitates the precious metal as solid metal. Just very, very finely divided. If there is excess nitric acid in the sample being tested, especially for Pd, the test results will show negative even if it is not. The excess nitric acid will stop the positive test results. Drop the silver from the sample as a chloride and destroy the excess nitric acid and then test the solution again.
kurtak
Well-known member
Sorry but that simply is not true - if you have PMs in solution you will always get a positive result - however - IF (the BIG IF) you have free oxidizer (nitric, chlorine etc.) in solution that positive result may well go away (re-dissolve) --- how fast the positive result goes away depends on two things (1) how much oxidizer is in solution AND how you do the test
I posted about this here (more detailed explanation) ------
https://goldrefiningforum.com/threa...or-palladium-perhaps.30890/page-2#post-324502
If you have LOTS of oxidizer in solution & you do your test in a spot plate the positive result may only last for a second (come & go in a heart beat) do the test with a Q-tip or paper towel & the positive result will last for a minute or longer - longer on paper towel then on a Q-tip
Edit to add; - that's why I always ask members (especially new members) to do there stannous test (when posting pics) on a Q-tip or paper towel instead of a spot plate
Kurt
Geo
Well-known member
Most of the people who come here doesn't have the years of experience that we have. For us, it would be easy to do. A beginner may not know to be watching for a flash of color but instead be watching for a solid color from the test. If they trust their ability and their chemicals, they could toss the sample as being negative. Harold told me when I first started that excess nitric acid will stop the stannous test from displaying a positive. I have been working on that assumption ever since. In my experience, testing a nitric acid leach from MLCC's with stannous chloride produces a soup of flavors. You have silver that turns into a white sludge, the tin itself reacts to the AR formed when you add stannous chloride with nitric acid and produces a frothy texture to the test. Any precious metal positive that does show up tends to be short lived at best in the newly formed AR. As a personal preference, I like to isolate a sample and destroy any free nitric acid first. That way the results are clear with less guessing. If I don't, it is still hard for me to determine a positive and a negative. I can imagine how hard it would be for a beginner.
Kurt and Geo, that is some good information from both of you. I lean toward the qtip for most of my testing these days and that stems from some tests early on that seemed to “change”. I know more about why that happens these days but have never had it explained that clearly.
Edited for spelling
Edited for spelling
kjavanb123
Well-known member
Hi
The primary result of smelting and cupeling fine size concentrate from 10kg sample was 0.113g gold.
All the gold recovered from smelting and cupeling coarse size concentrates are being dried for weighing.
The primary result of smelting and cupeling fine size concentrate from 10kg sample was 0.113g gold.
All the gold recovered from smelting and cupeling coarse size concentrates are being dried for weighing.
kurtak
Well-known member
kjavanb123
Well-known member
Hi
I have finished the calculations for smelting this sample.
Gold from smelting and cupeling fine size concentrate weighs 0.004 oz (0.113g)
Gold from smelting and cupeling coarse size concentrate weighs 0.003 Oz (0.085g)
Therefore total gold powder recovered from 10.798 kg gravel sample collected at a dried stream is 0.007 Oz (0.198g)
So that means 18g of gold per metric ton of this gravel sample.
It seems like a good area as most of the milling was already done by nature and sifting followed by gravity separation can produce coarse and fine concentrates to be smelted.
More projects coming soon as I am prospecting for PGMs.
I have finished the calculations for smelting this sample.
Gold from smelting and cupeling fine size concentrate weighs 0.004 oz (0.113g)
Gold from smelting and cupeling coarse size concentrate weighs 0.003 Oz (0.085g)
Therefore total gold powder recovered from 10.798 kg gravel sample collected at a dried stream is 0.007 Oz (0.198g)
So that means 18g of gold per metric ton of this gravel sample.
It seems like a good area as most of the milling was already done by nature and sifting followed by gravity separation can produce coarse and fine concentrates to be smelted.
More projects coming soon as I am prospecting for PGMs.
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